Under funding for the original U19, we addressed several hypotheses that have provided new insights into the fundamental, mechanistic understanding of regulatory T cells and how these pathways are altered in animal models of autoimmune disease and in the human diseases type I diabetes and multiple sclerosis. In addition, we have developed novel immunotherapeutic approaches to induce regulatory T cells using oral anti-CD3. The grant will continue to focus on these fundamental aims, reflecting the discoveries we have made over the past five years. In this renewal, the overall goals of this Autoimmunity Prevention Center Project are: 1) To determine, in human autoimmune disease, which of the CD4+CD25+ subsets of DR+ and DR" regulatory T cells are defective; 2) The identification of a "core set" of genes and proteins that are expressed on the "innate", CD4+CD25+ regulatory T cells; 3) To determine which of the "core sets" of genes and proteins are altered in the regulatory T cells found in blood and lymph nodes in patients with diabetes and MS; 4) To understand the mechanism of oral anti-CD3 and GRAIL transfection in T cells that allows the translation into human clinical trials by year five of the grant. The key goal is the development of specific drug targets and methods to induce the function of defective regulatory T cells in patients with autoimmune disease.